There is now a new Yelp app for the iPhone 3GS which according to the-gadgeteer, has an awesome Easter Egg: Augmented Reality.
Apparently they have been playing around with the new yelp for iPhone 3GS application and once downloaded apparently you are required to shake the iPhone 3GS 3 to 5 times to get the app to work properly and a massage about Monocle being activated pops up.
Once Monocle is activated the ‘Monocle’ button will appear, once you hit it you’ll get a camera view which shows restaurants with reviews shown in small tabs overlaying the camera view, although the reviewer says their iPhone 3GS compass didn’t seem to be all that accurate.